<Query readFrom="/posts">
posts.comments[n].author.name
)Query
as the "container", no need to dispatch actions for API requests<Query>
Loading = integer (1: initial, 2: pagination)
Paginate = { fetch: () => mixed, hasAny: boolean };
Pagination = { next: Paginate, prev: Paginate };
children: (props: { loading: Loading, error, data, pagination: Pagination })
In the most simple example, you just drop Query
into your component hierarchy where you need the data. Consider a page that lists all your blog posts, you render a header and footer, and query for the actual posts themselves.
import Query from 'react-redux-json-api';
import BlogPost from './BlogPost';
const BlogPosts = () => (
<article>
<header>Hello Blog</header>
<Query endpoint="/blog-posts">
{({ resources }) => resources.map(post => (
<section>
<a href={`/post/${post.id}`}>{post.attributes.title}</a>
</section>
))}
</Query>
<footer>© 2018</footer>
</article>
);
A very popular way to divide responsibilities in React apps is the container/presenter pattern. This is potentially a very clean pattern to use with our Query
component if you include this in your container component:
container.js
import Query from 'react-redux-json-api';
import BlogPosts from './presenter';
function Loading() {
return <div>I'm loading</div>;
}
function Container() {
return (
<Query endpoint="/blog-posts">
{({ loading, resources }) => {
if (loading) return <Loading />;
return <BlogPosts posts={resources} />
}}
</Query>
);
}
presenter.js
import BlogPost from './BlogPost';
export default function BlogPosts() {
return (
<article>
<header>Hello Blog</header>
{({ posts }) => posts.map(post => (
<section>
<a href={`/post/${post.id}`}>{post.attributes.title}</a>
</section>
))}
<footer>© 2018</footer>
</article>
);
}
Query
has the ability to cache the result set of executed requests in memory. The caching strategy is very simple, as the result set is stored in a cache key that corresponds to links.self
from the json:api body, falling back to the provided endpoint
if links.self
is not present.
If you would like to use the caching mechanism it is highly encouraged that links.self
is a permalink for all cached requests. This is important to avoid overlap or missing resources, see this detailed below. To opt-in set boolean prop enableCache
on your Query
instance; <Query endpoint="..." enableCache />
Let's use above example with blog posts. When a user initially loads our page, we will request /blog-posts
to retrieve the latest blog posts. We will also add buttons to go to next and prev pages:
<Query endpoint="blog-posts">
({ resources, links }) => (
<>
<BlogPosts posts={resources} />
{links.prev && <button onClick={links.next.load}>Prev</button>}
{links.next && <button onClick={links.next.load}>Next</button>}
</>
)
</Query>
Note: This is a naive implementation
This is an example response body for above code example, that will be error prone when cached. Let's say a user is vieweing the first page on your website, meanwhile you're creating a new blog post. When the user loads page 2, they will see the last blog post from page 1, on page 2 as well. Not only is this error prone when cached, but it's particularly bad because the result set from the first page is cached and will not refresh to the user.
GET /blog-posts
{
"links": {
"self": "/blog-posts",
"next": "/blog-posts?page=2"
},
"data": {
"...": {}
}
}
A response that would work well and prevent overlapping resources, uses some form of permalinking to a particular result set:
GET /blog-posts
{
"links": {
"self": "/blog-posts?fromTimestamp=1445412480",
"next": "/blog-posts?fromTimestamp=499165200"
},
"data": {
"...": {}
}
}
In this case links.self
does not reflect the requested URL, instead the server is set up to provide a link that is guaranteed to return the same result set. In this case the strategy is to use the timestamp of the latest blog post. This makes it a far more reliable key for our caching mechanism.